Singularity, lack of predictability, turnover, making do, these are only a few factors that compose the process-variability in the construction industry. The knowledge of stability in activities workflow is fundamental to allow a construction company to have accurate planning. This paper evidences the impact of variability into the construction planning by using Monte Carlo simulation. It was developed the Line of Balance (LOB) of a project and generated ten thousand lead times based on the probability distribution measured on gemba for these activities. According to the simulation, the variability has a high impact on projects process time. Moreover, the delays occurred in all ten thousand events of simulation and the average delay was 12 days. In addition, the average idle time observed was 10 days and it occurred because of process-time and flow variability. According to the study, the model proves the negative impact of variability in workflow and a model to calculate LOB buffers should be developed with the intend of presenting less chance of breaks in the flow and projects delay. So, researches concerning about how to dimension theses buffers should be conducted.
Lean construction, variability, Line of Balance, buffers, Takt Time Planning (TTP).
Deschamps, R.R. , Esteves, R.R. , Rossetto, R. , Tomazi, L.F. & Silva, G.G.M.P.D. 2015, 'The Impact of Variability in Workflow' In:, Seppänen, O., González, V.A. & Arroyo, P., 23rd Annual Conference of the International Group for Lean Construction. Perth, Australia, 29-31 Jul 2015. pp 826-835